Electric heaters



7 Jan. 26, 1965 5. J. TEMPLE 3,167,736

ELECTRIC HEATERS Filed March 13, 1962 INVENTOR. 510N11 J-T.EMPLE /Mmw/zz/ A TTOR/VE/5 United States Patent Ofifice 3,167,736 ELECTRICHEATERS Sidney J. Temple, littsburgh, Pa, assignor to Edwin L. WiegandCompany, Pittsburgh, Pa. Filed Mar. 13, 1962, Ser. No. 179,361 Claims.(Cl. 338-421) My invention relates to electric heaters, moreparticularly to a plug and socket connector for electric heaters, andthe principal object of my invention is to provide new and improvedconstructions of this character.

The heater of my invention is particularly useful in places where cleanworking conditions do not prevail, such as in construction jobs andshipyards where electric heat is used for preheating or other purposes.On such jobs, it is usual to connect the heater to a source ofelectrical current by a plug and socket connection.

In bad weather on construction jobs, or in shipyard welding, a greatamount of debris accumulates and the worker, when finished with use ofthe heater, usually disconnects the plug and socket and haphazardlydeposits the heater in any convenient place until its use is againrequired. Unfortunately, the socket, usually carried by the heater, hasdebris accumulated therein, and subsequent connection of the plug may beprevented, or a dangerous short-circuiting condition may be established.

My invention eliminates the difficulties encountered and dangers createdby debris accumulation and provides a socket which may be easilydismantled for cleaning. This, and other advantages will be apparentfrom the following description.

In the drawing accompanying this specification and forming a part ofthis application, there is shown, for purposes of illustration, severalforms which my invention may assume, and in this drawing:

FIGURE 1 is a perspective view showing the plug and socket of myinvention in disassembled condition,

FIGURE 2 is an enlarged longitudinal view taken through the socket,

FIGURE 3 is a plan view looking into the open end of the socket, and

FIGURE 4 is a fragmentary sectional view illustrating another form of myinvention.

Referring particularly to FIGURES 1 through 3, the invention thereindisclosed comprises a plug 1% and socket 11, the former being insertableinto the latter to complete an electrical circuit in known manner. Theplug has a cylindrical dielectric portion 12 and a pair of femaleterminals there-within, these terminals not being disclosed since theyare of standard design. The terminals are electrically connected to apower cable 14 which may lead from a suitable power line.

The plug has a pair of openings 15-15 in its end to receive maleterminals carried by socket 11. The plug and socket herein illustratedare of the twist-lock type and therefore the openings 15 are curved, asshown. However, the plug and socket may be of the push-pull type, inwhich case the openings would be straight to receive flat maleterminals.

The socket 11 comprises a shell 16 which may be formed of any suitablematerial, preferably a metal such as steel. The shell is preferablycup-shaped, as seen in FIGURE 2. An electric heating element 17 iscarried by the shell 16 and has a terminal portion entering the closedend of the shell.

The heating element is preferably of the type having a tubular metalsheath 18 in which is longitudinally disposed a heating resistor 19 inthe form of a coil of resistance wire. Suitable heat-conductingelectrical insulating material, such as powdered granular refractory maiatented Jan. 26, 15355 terial 20, compacted to a dense stone-likecondition, maintains the resistor spaced from the metal sheath.

The heating element illustrated is of the hairpin type, providing abight portion 21 and a pair of legs 22-22 disposed in generally parallelside-by-side relation. In accordance with usual construction, oppositeends of the resistor 19 are mechanically and electrically connected toterminal pins 23 23 which project outwardly of the opposite ends of theheater, as seen in FIGURE 2.

The ends of the heater pass through a pair of openings 2-i24 in thebottom wall 25 of the shell 16 and preferably a fused connection, suchas a silver brazed joint 26, holds the heater end to the bottom wall forrigidity of connection and to seal the openings 24 against passage ofdeleterious matter therethrough.

Referring again to FiGURE 2, each terminal pin 23 has a metallic sleeve27 of good conducting material secured to it and extending axiallytherefrom. A crimping of the sleeve about its terminal pin may besuificient connection, although it is preferred at the present time tosecure the sleeve to its terminal pin by a heliarc weld. Each sleeve 27has a screw-threaded opening entering from its free end to receive thethreaded shank 28 of a machine screw.

The refractory material 2%), or other insulation at the ends of theheater legs 2222, is preferably stopped short of filling the leg end, toprovide a cavity 29. An insulating material so is deposited within theshell at its closed end. Preferably, the material 35 is of the typewhich may be poured into the shell to settle on and above the bottomwall 25' and to fill the cavities 29 and all voids around the adjacentleg ends, terminal pins and lower ends of the sleeves 27. The material30 should have good adherence to the metal parts so as to seal the partsim mersed in it against moisture and other foreign matter.

An epoxy resin has been found suitable for this purpose.

A dielectric body 31 is removably disposed within the shell 16, and thisbody carries the male electrical connectors. The body is in the form ofa hard rubber disc which extends crosswise of the shell 16. One side 32of the disc is directed toward the bottom wall 25 of the shell and itsopposite side 33 is directed toward the open end of the shell. Acircular rim 34 may extend upwardly from the side 33 to protect theconnectors against electrical contact with the shell side wall.

The disc 31 is formed with a pair of openings 35 to closely passrespective sleeves 27. Each male connector as has a fiat base portion 37overlying the disc side 33 and firmly held thereagainst in any suitablemanner, such as by means of a tubular rivet 38 as in ordinaryconstructions. The base portion 37 of each male connector is formed withan opening 39 to freely pass the shank 23 of the machine screws.

With the machine screws fully threaded into respective sleeves 27, thescrew heads 40 firmly bear against male connector base portions 37 andthus maintain the dielectric body 31 and male connectors in properposition within the shell 16. In the event debris has accumulated withinthe shell, it is only necessary to remove the machine screws, wherebythe dielectric body 31 may be withdrawn from the shell, such as bygrasping the male connectors 36 and pulling the body 31 from the shell.The body 31 and male connector parts may be washed and cleaned, andseparately the interior of the shell 16 may also be I washed andcleaned, the epoxy resin 30 protecting the heater ends from moisture anddebris. Thereafter, the body may be replaced within the shell and themachine screws tightened to again effect the proper assembly.

In modification shown in FIGURE 4, the sleeves 27 are omitted and theterminal pins 23a extend through the openings 35a and base portions 37a,respectively. A

and

nut is threaded on the threaded extremity of each ter minal pin ZSatoeffect the assembly.

In view of the foregoing it will be apparent to those skilled in the artthat l have accomplished at least the principal object of my inventionand it will also be apparent to those skilled in the art that theembodiments her 'n described may be variously changed and modified,without departing from the spirit of the invention, and that theinvention is capable of uses and has advantages not herein specificallydescribed; hence-it will be appreciated that the herein disclosedembodiments are illustrative only, and that my invention is not limitedthereto.

1 claim:

1. An electric heater, comprising a sheathed electric heating element, aplug and socket connector for said heating element, including acup-shaped shell forming the socket and adapted to receive said plugthrough the open end thereof, said heating element being connected tosaid shell and having an end extending through an. opening in the closedend of said shell and further having a terminal pin extendinglongitudinally within said 7 shell, a disc-like dielectric bodyremovably positioned 'within said shell and having one side directedtoward the closed end of said shell and an opposite sidedirected towardopen end of said shell, a male electrical connector member carried bysaid body and adapted tobe electrically connected to a female electricalconnector member carried by said plug when the latter is inserted intosaid shell open end, said rnaleco'nnector member having a portionoverlying such opposite side of said body, a metal sleeve receiving andmechanically and electrically secured to said terminal pin, said bodyhaving an opening for passing said sleeve, and a capscrew threaded intosaid sleeve and having its head bearing against said male connectorportion.

2. An electric heater, comprising a'sheathed electric heating element, aplug and socket connector for said heating element, including a metalcup-shaped shell forming the socket and adapted to receive said plugthrough the openend thereof, said heating element having an endpositioned-through an opening in the closed end of said shell and havinga fused connection with the shell closed end to seal said opening, saidelement also having a terminal pin extending longitudinally within saidshell, a disc-like dielectric body removably positioned within saidshell and having one side directed toward the closed end of said shelland an opposite side directed toward the open end of said shell, a maleconnector member carried by said body and adapted to be electricallyconnected to a female electrical connectormember carried by said plugwhen the latter is inserted into said shell open end, said maleconnector member having a base portion overlying said opposite side ofsaid body and rigidly connected to the latter, a metal sleeve having oneend receiving and mechanically and electrically secured to said terminalpin and having an opposite internally threaded end, said body enemashaving an opening therethrongh for passing said sleeve from saidopposite side surface and for passing the threaded shank of a capscrewfrom said one side surface, the shank of said screw passing through anopening in said base portion and threaded into said sleeve opposite endwith its head bearing against said base portion.

3. Tie construction according to claim 2 wherein a resinous material isdisposed within said shell and adjacent to the closed end thereof andabout said terminal pin and sleeve.

4. The construction according to claim 3 wherein said resinous materialis introduced into said shell in pourable form and is permitted toharden.

5. An electric heater, comprising a sheat ed electric heating element, aplug and socket connector for said heating element, including acup-shaped metal shell forming the socket and adapted to receive saidplug through its open end, said heating element having a pair of legs injxtaposed relation, the terminal ends of said legs extending into saidshell through openings in the bottom of the latter and the nestingportion of said legs being disposed exteriorly of and extending fromsaid shell, a termi 1 pin eiitending outwardly of and the end of each ofsaid heater legs and longitudinally inwardly of said shell, insulatingmate ial Within said shell at its closed end and encasing said heaterleg ends to protect the same from contact with deleterious matter, adielectric body movable to W'hin said shell through the open end trereofand to a position overlying said insulating material, said body havingone side facing said insulating material and an opposite sid facing theopen end of said shell, a pair of male electrical connector me iberscarried by said body, each having a blade extending from said oppositeside and adapted to be connected to a female electrical.

connector member carried by said plug when the latter is inserted intosaid shell, each male connector member having a' base integral with itsblade and overlying said opposite side of said dielectric body, and amember overlying each of said bases and electrically connecting a baseto a respective terminal pin and simultaneously releasably holding saiddielectric body in position within said shell.

References fired in the file of this patent UNITED STATES PATENTS1,472,171 aynsWorth Oct. 30, 1923 1,881,881 Noble Oct. 11, 19321,970,149 Pugh Aug. 14, 193 2,227,159 Schnrig Dec. 31, 1940 2,245,602Morris June 17, 1941 2,310,325 Smith Feb. 9, 1943 2,430,593 Windsor Nov.11, 1947 2,664,548 Dec. 29, 1953 2,703,871 Woodhead Mar. 8, 19552,995,646 Aug. 8, 1961 3,048,805 Aug. 7, 1962

1. AN ELECTRIC HEATER, COMPRISING A SHEATHED ELECTRIC HEATING ELEMENT, A PLUG AND SOCKET CONNECTOR FOR SAID HEATING ELEMENT, INCLUDING A CUP-SHAPED SHELL FORMING THE SOCKET AND ADAPTED TO RECEIVE SAID PLUG THROUGH THE OPEN END THEREOF, SAID HEATING ELEMENT BEING CONNECTED TO SAID SHELL AND HAVING AN END EXTENDING THROUGH AN OPENING IN THE CLOSED END OF SAID SHELL AND FURTHER HAVING A TERMINAL PIN EXTENDING LONGITUDINALLY WITHIN SAID SHELL, A DISC-LIKE DIELECTRIC BODY REMOVABLY POSITIONED WITHIN SAID SHELL AND HAVING ONE SIDE DIRECTED TOWARD THE CLOSED END OF SAID SHELL AND AN OPPOSITE SIDE DIRECTED TOWARD THE OPEN END OF SAID SHELL, A MALE ELECTRICAL CONNECTOR MEMBER CARRIED BY SAID BODY AND ADAPTED TO BE ELECTRICALLY CONNECTED TO A FEMALE ELECTRICAL CONNECTOR MEMBER CARRIED BY SAID PLUG WHEN THE LATTER IS INSERTED INTO SAID SHELL OPEN END, SAID MALE CONNECTOR MEMBER HAVING A PORTION OVERLYING SUCH OPPOSITE SIDE OF SAID BODY, A METAL SLEEVE RECEIVING AND MECHANICALLY AND ELECTRICALLY SECURED TO SAID TERMINAL PIN, SAID BODY HAVING AN OPENING FOR PASSING SAID SLEEVE, AND A CAPSCREW THREADED INTO SAID SLEEVE AND HAVING ITS HEAD BEARING AGAINST SAID MALE CONNECTOR PORTION. 